The present invention relates to a disk array device and a control method therefor.
With the recent progress in IT technology, demand for high-performance and low-cost disk array devices with large volumes has increased. A disk array device has a number of disk drives arranged in arrays and configured based on a Redundant Array of Independent Inexpensive Disks (RAID) system. A host computer issues a write access command or a read access command to this disk array device to read or write data from/to the disk drives. Such a disk array device provides a redundant structure with regard to its internal devices—for example, it adopts a dual controller (duplex controller) structure aiming to enhance failure tolerance and achieve high performance (as in Japanese Patent Laid-Open Publication No. 2003-256150). A disk array device sometimes adopts Fibre Channel interfaces for both an interface to the host computer (hereinafter called a “front interface”) and an interface to the disk drives (hereinafter called a “back interface”) in order to achieve high-speed data transfer. In the above disk array device having the dual controller structure, one controller has one Fibre Channel Protocol controller for front-interface connection and one Fibre Channel Protocol controller for back-interface connection.